1# SPDX-License-Identifier: GPL-2.0-only 2config NILFS2_FS 3 tristate "NILFS2 file system support" 4 select CRC32 5 select LEGACY_DIRECT_IO 6 help 7 NILFS2 is a log-structured file system (LFS) supporting continuous 8 snapshotting. In addition to versioning capability of the entire 9 file system, users can even restore files mistakenly overwritten or 10 destroyed just a few seconds ago. Since this file system can keep 11 consistency like conventional LFS, it achieves quick recovery after 12 system crashes. 13 14 NILFS2 creates a number of checkpoints every few seconds or per 15 synchronous write basis (unless there is no change). Users can 16 select significant versions among continuously created checkpoints, 17 and can change them into snapshots which will be preserved for long 18 periods until they are changed back to checkpoints. Each 19 snapshot is mountable as a read-only file system concurrently with 20 its writable mount, and this feature is convenient for online backup. 21 22 Some features including atime, extended attributes, and POSIX ACLs, 23 are not supported yet. 24 25 To compile this file system support as a module, choose M here: the 26 module will be called nilfs2. If unsure, say N. 27